Intumescent materials are well known for use in fire rated applications. When subject to fire related conditions, such as very high temperatures, such intumescent materials are designed to expand to fill areas through which smoke and heat can pass in a fire. One such intumescent material for use in fire rated applications is described in U.S. Pat. No. 4,588,523.
As discussed in U.S. Pat. No. 4,588,523, intumescent materials have been used to fill voids left by burning or melting cable insulation. An example of the use of an intumescent material is in a poke through fitting is shown in U.S. Pat. No. 6,989,488, where the intumescent material is designed to fill a pass through hole in a fire rated floor.
In other environments, it is well known to use backer rods to fill spaces in joints, cracks or other openings (hereinafter “gaps”), commonly found in and between building panels such as floors, walls, etc., prior to applying a sealant. In this regard, many gaps are sufficiently deep, wide or extend through panels of several inches or more, making the use of high cost sealants to fill the entire gap inefficient. Backer rods are commonly known to be used to fill the gap to within about ½ inch or so of the surface, thus controlling the depth and amount of sealant needed, so that the sealant needs only to fill the portion of the gap from the backer rod to about the surface of the building panel(s).
This use of backer rods is especially important when the gaps are, for example, between floors of multistory buildings. In these environments, the gaps must be filled with a fire and/or smoke blocking functionality to keep fire and/or smoke from advancing upward from floor to floor. As expected, the sealants providing protection in such fire and/or smoke environments are more expensive than basic sealants.
Backer rods are manufactured by, among others, Backer Rod Manufacturing Inc., under the names MILE HIGH FOAM®, DENVER FOAM® and ULTRA BLOCK®. MILE HIGH FOAM® is a closed cell polyethylene backer rod serving as a backing for elastomeric and other applied caulking sealants. DENVER FOAM® is an open cell polyurethane backer rod serving as a backing for elastomeric and other applied caulking sealants.
ULTRA BLOCK® is a pre-engineered, textile fiberglass with fiberglass matt facing, containing approximately 30% by weight unexpanded vermiculite. This backer rod material is primarily used in fire rated construction joints, and is the subject of U.S. Pat. No. 4,622,251.
As described in U.S. Pat. No. 4,622,251, the ULTRA BLOCK® product comprises a porous sheathing material, comprised of an open weave material, and a porous fiber filling material, described as a ceramic fiber or mineral wool alone or mixed with small particles of minerals such as vermiculite and/or perolite. The filling material is wrapped in the sheathing material, formed in overlapping relationship, and the overlapping area of the sheathing material is sprayed with an adhesive material which passes through the sheathing material overlapping portions to maintain the sheathing material in fixed relation about the filler material.
However, the backer rod of U.S. Pat. No. 4,622,251 is difficult to manufacture and apply, since the filling material is a compacted material of fibers alone or with minerals. Additionally, there is only a minor physical expansion expected from the vermiculite and/or perolite optionally used with the filling material compressed within the sheathing material.
Therefore, there is a need for a better gap filling material for use in fire rated applications, including a backer rod that is especially suitable for fire rated applications.